OBJECTIVE: to propose a method to evaluate and maintain the efficiency of equipment commonly used in Brazil in order to obtain uniform results in phototherapy treatments in different services. MATERIAL AND METHODS: the radiometer/photometer used to measure spectral irradiance is locally manufactured and fulfills basic requirements. Measure standardization seeks to be applicable and reproducible to phototherapy devices employed in Brazil. The material necessary for measurements can be easily assembled by the neonatology staff, except for the radiometer. We searched Medline for papers relevant to this review published throughout the last 10 years. RESULTS: irradiance in phototherapy issues should be referred to as "medium spectral irradiance". We describe how to obtain medium spectral irradiance using fluorescent and halogen phototherapies. COMMENTS: the components of a radiometer/photometer are described. This knowledge is fundamental to understanding sensibility variations and to justifying differences in irradiance when ranges of radiometer recording are a little different. The standardization of this device will certainly simplify the comparison between results in different services. We also analyzed characteristics of different equipment used in phototherapy that might interfere with their irradiance.